UK police readied Saturday for more far-right protests across England after a third night of rioting linked to misinformation about a mass stabbing that killed three young girls.
The violence, which has seen scores of arrests and put Britain's Muslim community on edge, presents the biggest challenge yet of Labour Prime Minister Keir Starmer's month-old premiership.
It has also put hard-right agitators linked to football hooliganism in the spotlight at a time when anti-immigration elements are enjoying some electoral success in British politics.
Police were gearing for dozens of demonstrations after officers faced "serious and sustained levels of violence" during rioting in Sunderland, northeast England, on Friday night.
Eight people were arrested and three officers required hospital treatment following hours of "utterly deplorable" disturbances, Northumbria Police Chief Superintendent Helena Barron said.
Two officers remained in hospital early Saturday, she added.
Footage broadcast by the BBC showed a mob of several hundred rampaging in Sunderland's city centre, attacking police and setting fire to at least one car and a building next to a police office.
Other images shared on social media showed balaclava-clad youths throwing bricks and other missiles as fireworks and flares were let off.
"The shocking scenes we have witnessed in Sunderland this evening are completely unacceptable," Barron said, adding the "disorder, violence and damage" seen "will not be tolerated".
The unrest followed two nights of disturbances in several English towns and cities in the wake of Monday's frenzied knife attack in Southport, near Liverpool on England's northwest coast.
They were fuelled by false rumours on social media about the background of British-born 17-year-old suspect Axel Rudakubana, charged with several counts of murder and attempted murder over the attack at a Taylor-Swift dance party.
After violence in Southport late Tuesday, unrest rocked the northern cities of Hartlepool and Manchester as well as London 24 hours later, where 111 people were arrested outside Starmer's Downing Street residence.
In Southport, the mob threw bricks at a mosque, prompting hundreds of Muslim places of worship across the country to step up security amid fears of more anti-Islamic demonstrators.
Police blamed supports of the disbanded English Defence League, an anti-Islam organisation founded 15 years ago whose supporters have been linked to football hooliganism.
In Sunderland on Friday, rioters attacked police officers, set a police station and two cars on fire, and again targeted a mosque.
Anti-racism campaign group Hope Not Hate has identified more than 30 events planned for Saturday and Sunday.
Far-right social media channels have advertised "enough is enough" anti-immigrant rallies, and anti-facism groups have vowed to stage counter-protests.
London's Metropolitan Police said it had a "proportionate and risk-based" plan for rival pro-Palestinian and anti-immigration protests Saturday.
Counter protests were also expected in the central city of Nottingham while South Yorkshire police said Friday they knew of a planned protest in the town of Rotherham.
Prime Minister Keir Starmer has accused "thugs" of "hijacking" the nation's grief to "sow hatred" and pledged that anyone carrying out violent acts will "face the full force of the law".
He has announced new measures that will allow the sharing of intelligence, wider deployment of facial-recognition technology and criminal behaviour orders to restrict troublemakers from travelling.
Labour politicians have accused Reform UK party leader Nigel Farage of stoking the trouble.
At last month's election, his anti-immigrant Reform UK party captured 14 percent of the vote -- one of the largest vote shares for a far-right British party.
